An ignition interlock device or breath alcohol ignition interlock device (“IID”) is a mechanism, like a breathalyzer. Usually, an IID system is installed to a motor vehicle's dashboard. There is no universal clip for installation so often they are attached with adhesive, hook and loop fasteners, or screws, all of which can modify and “damage” the dashboard.
Before the vehicle's motor can be started, the driver first must exhale into the device. If the resultant breath-alcohol concentration analyzed result is greater than the programmed blood alcohol concentration, the device prevents the engine from being started. At random times after the engine has been started, the IID will require another breath sample. The purpose of this is to prevent a friend from breathing into the device, enabling the intoxicated person to get behind the wheel and drive away. If the breath sample isn't provided, or the sample exceeds the ignition interlock's preset blood alcohol level, the device will log the event, warn the driver and then start up an alarm (e.g., lights flashing, horn honking, etc.) until the ignition is turned off, or a clean breath sample has been provided.
In the end, people do not like having IID's installed in their cars because of the installation modifications that are required to their dashboards. They are also embarrassed by them. IIDs draw attention to themselves by, in some cases, making a car's horn honk or flash lights, but certainly when a person has to use them (blow into them, etc.).